Tuesday, February 19, 2013

Making a 2m Rokkaku - Preparation

Part 1 of 4
I have made kites all my life, but nothing as big or serious as this one, and have a fair bit of sewing experience. Between high school and uni I spent some time as a sailmaker's assistant and made my own sailboard sails. Wife Virginia encouraged me to use her precious Pfaff Tiptronic 2030 so I was almost set to go.

Great advice given by expert sewers is "new project, new needle". Respected kite maker Gary Engvall recommends that a size 90 universal point needle is right for ripstop. So I bought a packet of size 90 universal points and 2 rolls of Gutermann polyester thread.

A Rokkaku kite is very simple being basically a flat hexagon with patches and pockets added and there are plenty of plans and How-to websites available.

I decided on a 5:4:3 size ratio and 2m high design. This means that the height is 200cm, width 160cm and main body 120cm high. This is a good size for a wide wind range similar to the Skydogs and Premier Rokkaku kites. It should have roughly twice the line pull of a ITW Levitation Delta making it perfect for lifting an SLR in Bft 3 and 4 and lighter rigs in almost any wind.

Now for sourcing the materials. Ripstop nylon varies greatly. Don't go to a normal material shop and buy their cheap ripstop, it's heavy, stretchy and only good for shower curtains, kite bags and tails.
For kites you need the stiff crackly stuff used for spinnakers. The most common weight seems to be 3/4oz. I used Emma Kites $6.00 ripstop. Although it's very light weight it worked really well. Might try ITW, Kitebuilder or a local sailmaker's spinnaker cloth next time.

You also need some stiffer reinforcing cloth for corner patches and other stress points. I had some cordura for my kite but dacron sailcloth is more often used. 1" wide webbing is also needed for corner pockets and spar loops.

Here is an A4 sized gif of my kite plan. Feel free to download and print it. Red seam allowances are not to scale.

It's important to cut out the panels with the long edges aligned along the warp or down the length of the piece of cloth. That way the finished kite will hold its shape better with less ugly stretch wrinkles. The warp has less stretch than the weft.

I made a template for the triangle panel which made marking out
much quicker.

Mark out the finished size of the panels on your ripstop in clear lines (to sew along later) then add the seam and hem allowances (for cutting out)

Next post will discuss sewing together the panels and adding reinforcing patches